As mobile terminal charging technologies are in the continuous development, charging needs become increasingly simple, fast and diversified. Consequently, wireless charging technologies are generated on demand. Also known as inductive charging, wireless charging stems from the wireless power transmission technologies, in which energy is transmitted by power supply equipment (chargers) to electric devices by means of inductive coupling to charge batteries. Energy transmission between the power supply equipment and the electric devices can be implemented through inductive coupling. Therefore, the power supply equipment and the electric devices may implement nonconductive contact point exposure without wired connection.
During wireless charging, receivers of the electric devices are charged by converting AC signal to 5V DC signal. Unlike standard chargers (wired chargers), the output signal is only a power line and a ground wire. Charging managers of most of electric devices in the market regard, by default, chargers only provided with power lines and ground wires as a computer connection entry USB mode. In this mode, charging current less than or equal to 500 mA (such as 450 mA) can be supplied. Counting system consumption in, current actually available for battery charging is only about 400 mA, which leads to a slow charging process. Therefore, the above mode is slow in charging and unable to meet charging demands of users, which affects the application of the wireless charging technologies.
To improve the wireless charging efficiency, most of electric devices having wireless charging functions are provided with different charging managers for wired charging and wireless charging, which increases costs of the electric devices and layouts of printed circuit boards (PCBs). If one charging manager is used, the wireless charging is configured as AC charging since the charge manager has completed the enumeration of charge types. Thus, when a computer or OTG equipment is connected during wireless charging, it is impossible to recognize the computer or OTG equipment. If the wireless charging is interrupted, after the USB connection is disconnected or the OTG equipment is removed, it is impossible to recover the wireless charging because the wireless charging communication is disconnected. That is, because of cutoff of wireless charging, the charging manager performs enumeration of charge types. Therefore, it is still impossible to recognize disconnection of the USB connection or removal of the OTG equipment.
In summary, the method of using two charging managers has a great impact on the electric devices in cost and PCB layout, which is to the disadvantage of application of the electric devices. However, if the method of using one charging manager is adopted, it is impossible to recognize connection of a computer or OTG equipment after completing enumeration of wireless charging, and it is impossible to recognize disconnection of the USB connection or removal of the OTG equipment after completing enumeration of connection of the computer or OTG equipment. Therefore, the method of using one charging manager is also unavailable for wireless charging.
This section provides background information related to the present disclosure which is not necessarily prior art.